1. Field of the Invention
Systems for mobile communication have increasingly gained in importance in recent years. Their spread is aided by the introduction of standards such as GSM (Global System for Mobile Communication) and, in the meantime; it has also become possible to communicate outside the borders of one's own country and network operator.
If a telephone call originates in a foreign country, the network operator of the visited public land mobile network (VPLMN) currently usually earns 70% of the fees paid by the network subscriber whereas the operator of the home public land mobile network (HPLMN) only receives 30%.
2. Description of the Prior Art
The customer of telecommunication networks, mobile radio networks, is already being offered a multiplicity of telecommunication services. To be able to offer new services rapidly and independently of manufacture and network operator, if possible, including the existing infrastructure, the concept of the Intelligent Network has been developed. A standardized concept which defines the IN architecture has been worked out in the ITU (see Standards Q.1200 ff).
In a further development, CAMEL (Customized Application for Mobile Network Enhanced Logic, see also GSM 02.78) was developed in which IN features were introduced into the GSM architecture. CAMEL simplifies roaming both internationally and between networks of different operators and creates a uniform protocol for accessing CAMEL servers in other GSM networks.
It is an object of the present invention, therefore, to specify a solution to the abovementioned problem in international or inter-provider roaming.
It is another object of the present invention to implement a call back service in a mobile radio network.